Are specific fire door gaps a legal requirement?

[Guest John]

Hi Neil, 

We currently have doors with over the 4mm gap and no amount of adjustment is complying with the regulations. Can you pack hinges on a fire door? I think I read about suitable solid packing, not sure if that's just the door frame.

[Neil ashdown]

Hinge blades may be packed with intumescent sheet materials. eg. 

[Guest Mark]

Hi would a fire door with a gap of 4.2 mm fail impaction 

[Neil ashdown]

The guidance document 'BS 8214: 2016 Timber-based fire door assemblies - Code of practice' recommends a gap of 2mm to 4mm, so on this basis 4.2mm would be non-compliant.

However, this article may be useful https://afdi.org.uk/fire-door-industry-news/fire-doors-what-is-compliance/

[Guest Paul]

Is there a requirement of a gap between the door frame and structural opening or can it be a snug fit and sealed with intumescent mastic ?

[Tom Sutton]

Not than I am aware of, the closer to the structural opening, the better I would think.

[Neil ashdown]

This matter is dealt with in the Standard BS 8214: 2016 https://landingpage.bsigroup.com/LandingPage/Undated?UPI=000000000000226297

[Guest Daniel]

I do a lot of fire door maintenance and I fit a lot of smoke seals to fire doors in various building. Most building are very old and have old doors with no manufactories labels on. If I come across a fire door with 4mm gap on the hinge side but a 6 or 7mm gap on the lock side I normally put smoke seals with 9mm brush. That way the brush is still touching the frame and doing it's job stopping the smoke and if the fire got that close the intumescent part would easily expand to close the gap. 

Is this acceptable?

The reason I ask is because most if not all clients I do work for will not change or can't afford to change all their fire doors because the doors are 2 to 3mm too small. 

Any advise on this would be great. 

[Neil ashdown]

The relevant British Standard, BS 8214, states "A typical gap to achieve good fire performance is between 2mm and 4mm".   Excessive door leaf to door frame gaps could cause failure of the door to meet the required fire resistance performance. 

[Guest Jake]

I work in schools and I have over 1.500 fire doors to keep on top of . 

As these schools were built in 2005 to 2010 I have a lot of problems with gaps now.  If the fire doors were installed at that time  do I have to get the gap to 4mm . As I've been told if it's remedial work I'm  allow it upto  5mm . Is this true ?

[Mike North]

The 2-4 gap quoted refers to the installation of the door, any deviation from this over time would be risk based in line with the RRO.

If you are happy with a 5 mm gap and are confident that you can convince a man in a curly wig, then yes 

[Guest Nigel]

Hi Neil, in a number of the buildings that my organisation owns the gap on the verticals on some of the fire doors is outside the 2-4mm tolerance.  In terms of understanding the legislation, where a gap of 6mm exists, but the smoke seal installed closes the gap down to 2mm, would this be considered a compliant door?

[Neil Ashdown MAFDI]

As far as fire door specific standards are concerned its non-compliant and the smoke seals are ineffective due to the 2mm gap. Refer to BS 8214: 2016.

So in terms of fire safety, this would be the subject of an assessment by a Fire Risk Assessor and depend largely the door function, location and the use of the building. 

[Ronan]

On 30/06/2022 at 20:49, Guest Daniel said:

I do a lot of fire door maintenance and I fit a lot of smoke seals to fire doors in various building. Most building are very old and have old doors with no manufactories labels on. If I come across a fire door with 4mm gap on the hinge side but a 6 or 7mm gap on the lock side I normally put smoke seals with 9mm brush. That way the brush is still touching the frame and doing it's job stopping the smoke and if the fire got that close the intumescent part would easily expand to close the gap. 

Is this acceptable?

The reason I ask is because most if not all clients I do work for will not change or can't afford to change all their fire doors because the doors are 2 to 3mm too small. 

Any advise on this would be great. 

I'm trying to understand the same. If the brush touches the frame in my opinion it should be ok. Especially if it's 6mm for example. The intumescent expands enough to cover that gap. I'm no expert but I think the 4mm rule is just a rule, not required by law. 

[Neil Ashdown MAFDI]

The 4mm max gap is specified by the fire door manufacturer based on their evidence of performance from fire resistance tests to BS 476-22 and/or EN 1634-1.  So its a requirement otherwise the fire performance certification becomes void. 

Obviously, once the door is installed at the building those gaps might change when the door is subject to high humidity or excessive temperatures. Then it becomes a maintenance issue and the Fire Risk Assessor/Fire Safety Officer for the building should be consulted where there are issues around maintaining the 2mm to 4mm gap. Prioritising the cold smoke spread issue might well be a suitable strategy but its a decision for the FRA/FSO rather than the maintenance team. 

There is also guidance at BS 8214: 2016 stating gaps should be 2mm to 4mm for optimum fire resistance performance.

[Guest Ian MP]

As a managing agent, I have been asked to advise on existing fire doors, flat front doors opening on to the escape route, in a 1990's block of purpose built flats.

I know that where the gaps on edges are over 4mm it is recommended that a suitable competent fire door contractor is engaged to adjust the door.

However, where gaps are 1.5mm, which is under the guidance of 3mm to 4mm +-1mm, does a flat owner need to instruct a contractor to reduce the door so gaps are larger?  id the door closes I cannot see the advantage in enlarging the gaps.

[Neil Ashdown MAFDI]

The recommendation is 2mm to 4mm.  More than 4mm could be an issue affecting the restricted spread of smoke and potentially premature failure of the door in a fire.  Less than 2mm could mean that the door fails to self-close and latch correctly (eg. due to binding on a smoke seal), therefore inspect each door to make sure any tight gaps do not affect the ability of the door to self-close completely. 

Edited February 19 by Neil Ashdown MAFDI
To correct a typo

[Guest Dave B]

So we have just upgraded solid oak doors that are over 90 years with original oak frames .We have upgraded the leaded light glazing in the doors by applying a pyro glass to the inside of the door over the leaded light with new oak beads and and intumescent tape to beads and existing leaded glass.

The doors over time have had various locks,bolts etc fitted to which we have removed and filled all old mortices holes etc with solid oak and fitted new fire rated locks,latches .

The panel at bottom of door has been upgraded with intumescent card and new oak faced panel to hide .

Now these doors have warped,dropped been eased and messed about with over time (every door here  is different ) and all bit of a mess really.

We have jacked up re glued and doweled loose tennons ripped down and planted on solid oak to stiles ( min of 25mm ) to close the large gaps on some of the doors 

Planted on solid oak to bottoms where needed and surface mounted drop down bar fitted.

15mm intumescent brush strips have fitted to stiles and head of doors and 3 hinges on intumescent pads .

So as you can imagine maintaining a 3mm/ 4mm gap around these doors is a very tough task. New doors would have been easier but wasn’t an option in this old building.

The building surveyor has been round with his little gauging tool and said some of the doors are not exceptable . We are talking maybe a 5mm gap 6mm max on some of the doors .

New quality overhead door closers have been fitted and we struggle to get the doors to close due to the air pressures between the flat and the common way especially with the drop down bar and 3mm /4mm gaps . Open a window and bang 💥 the doors slam.

Is this surveyor being unreasonable in this situation? The fire officer was very happy with the standard of work when called to site .

Look forward to any answers … cheers .

 

[Mike North]

Its finding the right surveyor who is use to dealing with historical buildings. 

By taking a holistic approach to an overall fire risk assessment you can let somethings slide and beef others up, an example would be to put smoke heads either side of the door in lieu of closing the gaps.  Of course this is all dependant of the risks and the purpose group of the property

[AnthonyB]

Possibly 'code hugging' rather than taking into account the actual risks & other mitigating measures (e.g. fire detection & warning system to a higher category than usually required)

When you say 'surveyor' who exactly are they are what are they doing? Is it a Building Control matter, insurance visit or fire risk assessment? There are insurers and fire risk assessors who specialise in heritage buildings and will take a holistic view, sounds like you need one!